Well, yeah. Those with better-adapted immune systems survived. That can always work, but as a society, we made the decision that it’s better to fight it and try to overcome it through technology than to lose a fraction of the human race to disease.

The immune system is the answer. In the human body, infections sometimes succeed simply by growing and spreading faster than the immune system can keep up with. For most infections treated with antibiotics, their numbers are lowered enough to be contained and eradicated by the immune system. In the petri dish, the…